Institut für Immunologie und Transfusionsmedizin, Ernst-Moritz-Arndt Universität, Greifswald, Germany.
Nucleic Acids Res. 2010 Apr;38(7):2268-78. doi: 10.1093/nar/gkp1220. Epub 2010 Jan 13.
Cellular differentiation and development of germ cells critically depend on a coordinated activation and repression of specific genes. The underlying regulation mechanisms, however, still lack a lot of understanding. Here, we describe that both the testis-specific transcriptional activator CREMtau (cAMP response element modulator tau) and the repressor GCNF (germ cell nuclear factor) have an overlapping binding site which alone is sufficient to direct cell type-specific expression in vivo in a heterologous promoter context. Expression of the transgene driven by the CREM/GCNF site is detectable in spermatids, but not in any somatic tissue or at any other stages during germ cell differentiation. CREMtau acts as an activator of gene transcription whereas GCNF suppresses this activity. Both factors compete for binding to the same DNA response element. Effective binding of CREM and GCNF highly depends on composition and epigenetic modification of the binding site. We also discovered that CREM and GCNF bind to each other via their DNA binding domains, indicating a complex interaction between the two factors. There are several testis-specific target genes that are regulated by CREM and GCNF in a reciprocal manner, showing a similar activation pattern as during spermatogenesis. Our data indicate that a single common binding site for CREM and GCNF is sufficient to specifically direct gene transcription in a tissue-, cell type- and differentiation-specific manner.
细胞分化和生殖细胞的发育严重依赖于特定基因的协调激活和抑制。然而，潜在的调控机制仍然缺乏很多理解。在这里，我们描述了睾丸特异性转录激活因子 CREMtau（环磷酸腺苷反应元件调节剂 tau）和抑制因子 GCNF（生殖细胞核因子）都具有重叠的结合位点，该结合位点单独足以在异种启动子背景下在体内指导细胞类型特异性表达。由 CREM/GCNF 位点驱动的转基因表达可在精母细胞中检测到，但在任何体细胞组织或生殖细胞分化的任何其他阶段都无法检测到。CREMtau 作为转录基因激活因子，而 GCNF 抑制这种活性。这两个因子竞争结合相同的 DNA 反应元件。CREM 和 GCNF 的有效结合高度依赖于结合位点的组成和表观遗传修饰。我们还发现 CREM 和 GCNF 通过其 DNA 结合结构域相互结合，表明这两个因子之间存在复杂的相互作用。有几个睾丸特异性靶基因受到 CREM 和 GCNF 的相互调节，其表达模式与精子发生相似。我们的数据表明，CREM 和 GCNF 的单个共同结合位点足以特异性地以组织、细胞类型和分化特异性的方式指导基因转录。
